Polyoxyethylene compound having multiple hydroxyl groups at end, and contact lens

ABSTRACT

Provided is a silicone contact lens having surface hydrophilicity and surface lubricity. It has been confirmed that a silicone contact lens including, on its surface, a graft polymer chain derived from a polyoxyethylene compound having a plurality of hydroxyl groups at a terminal thereof has surface hydrophilicity and surface lubricity.

TECHNICAL FIELD

The present invention relates to a polyoxyethylene compound having aplurality of hydroxyl groups at a terminal thereof, and to a contactlens.

The present application claims priority from Japanese Patent ApplicationNo. 2016-092130, which is incorporated herein by reference.

BACKGROUND ART

A silicone hydrogel contact lens has been known as one kind of contactlens. The silicone hydrogel contact lens has been expected to suppresseye diseases resulting from the oxygen deficiency of a cornea, such asan infectious disease, corneal vascularization, and corneal endothelialcell damage, because the lens has oxygen permeability drastically higherthan that of a related-art contact lens. Meanwhile, silicone is amaterial having extremely strong hydrophobicity, and hence has involveda problem in that when the silicone is used as it is as a contact lens,corneal damage due to a tear breakup or friction with an ocular tissuein association therewith occurs. In view of the foregoing, companiesdeveloping silicone hydrogel lenses have been modifying the surfaces ofthe lenses through various methods to transform their physicalproperties into those applicable to eyes.

As a method of modifying the surface of a contact lens, a methodinvolving using graft polymerization has already been known in the art.In Patent Literature 1, there is a description of a method involvingsubjecting the surface of a polysiloxane contact lens to graftpolymerization with N,N-dimethylacrylamide to improve the hydrophilicityof the surface of the contact lens while maintaining its oxygenpermeability.

In Patent Literature 2, there is a description of a method involvingsubjecting the surface of a base material, such as a polysiloxane, tograft polymerization with methacrylic acid, sodium methacrylate, sodiumvinyl sulfonate, or sodium styrene sulfonate to improve thehydrophilicity of the surface of the base material.

In Patent Literature 3, there is a description of a method involvingsubjecting a silicone hydrogel base material to graft polymerizationwith a special zwitterionic group-containing monomer to improve thehydrophilicity and lubricity of the surface of the base material.

In Patent Literature 4, there are descriptions of a method involvingmixing a water-soluble polymer, which is obtained by polymerizing apolyoxyethylene compound having a free radical-polymerizable group andhaving a weight-average molecular weight of from about 300 to about 500,into the package preservation solution of a hydrogel lens in advance,and treating the mixture with an autoclave to cause the polymer toadhere to the surface of the lens, and a method involving dissolving thewater-soluble polymer in a monomer mixture in advance, and polymerizingthe monomer mixture to provide a lens, thereby modifying the surface ofthe lens.

However, a method involving improving the hydrophilicity of the surfaceof a silicone hydrogel lens with a polyoxyethylene derivative having aplurality of hydroxyl groups at a terminal thereof has not been knownyet.

CITATION LIST Patent Literature

[PTL 1] JP 02-228309 A

[PTL 2] JP 09-506665 A

[PTL 3] JP 2011-81394 A

[PTL 4] JP 2008-520668 A

SUMMARY OF INVENTION Technical Problem

That is, an object of the present invention is to provide a siliconecontact lens having surface hydrophilicity and surface lubricity.

Solution to Problem

The inventors of the present invention have made extensiveinvestigations with a view to achieving the object, and as a result,have confirmed that a silicone contact lens including, on its surface, agraft polymer chain derived from a polyoxyethylene compound having aplurality of hydroxyl groups at a terminal thereof (hereinaftersometimes referred to as “monomer of the present invention”) has surfacehydrophilicity and surface lubricity. Thus, the inventors have completedthe present invention.

That is, the present invention is as described below.

[1] A polyoxyethylene compound, which is represented by the followingformula (1):

where n represents from 2 to 2,260, and R¹ represents a hydrogen atom ora methyl group.

[2] A silicone contact lens, including, on a surface thereof, a graftpolymer containing a constituent unit represented by the followingformula (1′):

where n represents from 2 to 2,260, and R¹ represents a hydrogen atom ora methyl group.

[3] A contact lens, including a constituent unit represented by thefollowing formula (1′):

where n represents from 2 to 2,260, and R¹ represents a hydrogen atom ora methyl group.

[4] A polyoxyethylene compound according to the above-mentioned item 1,wherein the n represents from 5 to 230, and the R¹ represents a methylgroup.

[5] A silicone contact lens according to the above-mentioned item 2,wherein the n represents from 5 to 230, and the R¹ represents a methylgroup.

[6] A contact lens according to the above-mentioned item 3, wherein then represents from 5 to 230, and the R¹ represents a methyl group.

[7] A method of producing a silicone contact lens including, on asurface thereof, a graft polymer containing a constituent unitrepresented by the following formula (1′):

where n represents from 2 to 2,260, and R¹ represents a hydrogen atom ora methyl group.

[8] A method of producing a contact lens including a constituent unitrepresented by the following formula (1′):

where n represents from 2 to 2,260, and R¹ represents a hydrogen atom ora methyl group.

[9] A surface treatment agent for a contact lens, including apolyoxyethylene compound represented by the following formula (1):

where n represents from 2 to 2,260, and R¹ represents a hydrogen atom ora methyl group.

[10] A surface treatment method for a contact lens, including using apolyoxyethylene compound represented by the following formula (1):

where n represents from 2 to 2,260, and R¹ represents a hydrogen atom ora methyl group.

[11] A polyoxyethylene compound for a surface treatment of a contactlens, which is represented by the following formula (1):

where n represents from 2 to 2,260, and R¹ represents a hydrogen atom ora methyl group.

[12] A use of a polyoxyethylene compound represented by the followingformula (1) as production of a surface treatment agent for a contactlens:

where n represents from 2 to 2,260, and R¹ represents a hydrogen atom ora methyl group.

Advantageous Effects of Invention

The silicone contact lens of the present invention has surfacehydrophilicity and surface lubricity.

DESCRIPTION OF EMBODIMENTS

The present invention is described in more detail below.

[Monomer of the Present Invention]

A monomer of the present invention is a polyoxyethylene compound havinga plurality of hydroxyl groups at a terminal thereof, and is representedby the following formula (1).

In the formula (1), n represents from 2 to 2,260, and R¹ represents ahydrogen atom or a methyl group. When the polymerization degree nbecomes 1 or less, sufficient hydrophilicity and sufficient lubricitycannot be imparted to the surface of a contact lens. When the nrepresents 2,261 or more, the viscosity of the monomer increases to makeit difficult to uniformly treat the surface of the contact lens with themonomer, and hence a function of the contact lens is inhibited. The n isnot particularly limited as long as the n falls within the range of from2 to 2,260, and the n may represent from 2 to 250, from 17 to 200, from50 to 150, from 75 to 135, from 90 to 120, from 5 to 230, or from 17 to222, and preferably represents from 17 to 1,000, more preferablyrepresents from 17 to 500, and most preferably represents from 17 to200.

[Method of Synthesizing Monomer of the Present Invention]

Although a method of synthesizing the monomer of the present inventionis not particularly limited, the following method may be given as anexample thereof.

The monomer of the present invention can be obtained by deprotecting,for example, a polyoxyethylene compound A described below through aknown method.

Specifically, the pH of the polyoxyethylene compound A is reduced, andextraction is performed with an organic solvent (e.g., chloroform ortoluene). Further, the extract is dehydrated with a dehydrating agent(e.g., magnesium sulfate), and the dehydrating agent is removed. Next,desolvation is performed. Thus, the monomer of the present invention canbe obtained.

(Polyoxyethylene Compound A)

The polyoxyethylene compound A may be synthesized from a polyoxyethylenecompound “a” described in JP 2012-214747 A, and is represented by thefollowing formula (3).

In more detail, the polyoxyethylene compound A may be obtained byturning the polyoxyethylene compound “a” {the following formula (2)}into an ester through a method known per se.

Specifically, the polyoxyethylene compound “a” is dissolved in anorganic solvent (e.g., toluene), and the solution is dehydrated. Forexample, triethylamine and acryloyl chloride {the monomer of the presentinvention to be finally obtained is such that the R¹ in the formula (1)represents a hydrogen atom} or methacryloyl chloride {the monomer of thepresent invention to be finally obtained is such that the R¹ in theformula (1) represents a methyl group} are added to the residue, and themixture is subjected to a reaction for several hours.

Next, triethylamine hydrochloride in the organic solvent is removed, andimpurities are removed by extraction or the like, followed bydesolvation or the like. Thus, the monomer of the present invention canbe obtained.

[Silicone Contact Lens Including, on its Surface, Graft PolymerContaining Constituent Unit Based on Monomer of the Present Invention]

A silicone contact lens including, on its surface, a graft polymercontaining a constituent unit based on the monomer of the presentinvention (derived from the monomer of the present invention) includes,on the surface, a graft polymer chain containing a constituent unitrepresented by the following formula (1′). In more detail, the surfaceof the silicone contact lens including, on the surface, the graftpolymer containing a constituent unit based on the monomer of thepresent invention is chemically modified with the graft polymer chaincontaining a constituent unit represented by the following formula (1′).

In the formula (1′), n represents from 2 to 2,260, and R¹ represents ahydrogen atom or a methyl group. When the n represents 1 or less,sufficient hydrophilicity and sufficient lubricity cannot be imparted tothe surface of a contact lens. When the n represents 2,261 or more, theviscosity of the monomer increases to make it difficult to uniformlytreat the surface of the contact lens with the monomer, and hence afunction of the contact lens is inhibited. The n is not particularlylimited as long as the n falls within the range of from 2 to 2,260, andthe n may represent from 2 to 250, from 17 to 200, from 50 to 150, from75 to 135, from 90 to 120, from 5 to 230, or from 17 to 222, andpreferably represents from 17 to 1,000, more preferably represents from17 to 500, and most preferably represents from 17 to 200.

When Surface Treatment Object is Silicone Hydrogel

Although the following materials may be given as examples of a siliconemonomer to be used for a silicone hydrogel contact lens base materialincluding, on its surface, the graft polymer containing a constituentunit based on the monomer of the present invention,3-[tris(trimethylsiloxy)silyl]propyl methacryloyloxyethyl succinate (seeWO 2010/082659 A1) is preferred.

Examples of (meth)acrylates each having a polydimethylsiloxane skeletoninclude α-methyl-ω-methacryloyloxypropyl polydimethylsiloxane(weight-average molecular weight: 1,000) and α,ω-dimethacryloyloxypropylpolydimethylsiloxane (weight-average molecular weight: 1,000). Forexample, FM-0711 or FM-7711 sold from JNC Corporation may be used.

Examples of (meth)acrylates each having a trimethylsiloxy group include3-[tris(trimethylsiloxy)silyl]propyl (meth)acrylate (TRIS),3-[bis(trimethylsiloxy)methylsilyl]propyl (meth)acrylate, and3-[(trimethylsiloxy)dimethylsilyl]propyl (meth)acrylate.

Examples of (meth)acrylamides each having a trimethylsiloxy groupinclude 3-[tris(trimethylsiloxy)silyl]propyl(meth)acrylamide,3-[bis(trimethylsiloxy)methylsilyl]propyl(meth)acrylamide, and3-[(trimethylsiloxy) dimethylsilyl]propyl (meth) acrylamide.

Examples of styrenes each having a trimethylsiloxy group include[tris(trimethylsiloxy)silyl]styrene,[bis(trimethylsiloxy)methylsilyl]styrene, and[(trimethylsiloxy)dimethylsilyl]styrene.

Examples of vinyl carbamates each having a trimethylsiloxy group includeN-[3-[tris(trimethylsiloxy)silyl]propyl] vinyl carbamate,N-[3-[bis(trimethylsiloxy)methylsilyl]propyl] vinyl carbamate, andN-[3-[(trimethylsiloxy)dimethylsilyl]propyl] vinyl carbamate.

When 3-[tris(trimethylsiloxy)silyl]propyl methacryloyloxyethyl succinateis used, polymerization components may be the silicone monomer alone,but typically include any other monomer polymerizable with the siliconemonomer. In this case, the usage amount of the silicone monomer istypically from 10 parts by mass to 80 parts by mass, preferably from 40parts by mass to 80 parts by mass with respect to 100 parts by mass ofthe monomer composition of the silicone hydrogel contact lens basematerial.

Further, any other monomer that has been generally used as a monomer tobe used for a silicone hydrogel contact lens may be appropriatelyselected and used.

Preferred examples of the other monomer to be used for the siliconehydrogel contact lens base material for the purpose of controlling thewater content of the contact lens include water-soluble monomers, suchas (meth)acrylic acid, itaconic acid, crotonic acid, cinnamic acid,vinylbenzoic acid, 2-(meth)acryloyloxyethyl phosphorylcholine, apolyalkylene glycol mono(meth)acrylate, a polyalkylene glycol monoalkylether (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2,3-dihydroxypropyl(meth)acrylate, glycerol (meth)acrylate, N-vinylformamide,N-vinylacetamide, N-methyl-N-vinylacetamide, and N-vinyl-2-pyrrolidone.Of those, from the viewpoint of the controllability of the water contentof the contact lens, 2-hydroxyethyl (meth)acrylate andN-vinyl-2-pyrrolidone are more preferred. The usage amount of any suchmonomer is typically from 10 parts by mass to 50 parts by mass,preferably from 20 parts by mass to 40 parts by mass with respect to 100parts by mass of the monomer composition of the silicone hydrogelcontact lens base material.

Examples of the other monomer to be used for the silicone hydrogelcontact lens base material for the purpose of controlling theflexibility of the contact lens include a polyalkylene glycolbis(meth)acrylate, trimethylolpropane tris(meth)acrylate,pentaerythritol tetrakis(meth)acrylate, N,N-dimethyl(meth)acrylamide,N,N-diethyl(meth)acrylamide, N,N-di-n-propyl(meth)acrylamide,N,N-diisopropyl(meth)acrylamide, N,N-di-n-butyl(meth)acrylamide,N-(meth)acryloylmorpholine, N-(meth)acryloylpiperidine,N-vinylcaprolactam, N-vinyloxazolidone, 1-vinylimidazole,N-vinylcarbazole, vinylpyridine, and vinylpyrazine. The usage amount ofany such monomer is typically from 10 parts by mass to 50 parts by mass,preferably from 20 parts by mass to 40 parts by mass with respect to 100parts by mass of the monomer composition of the silicone hydrogelcontact lens base material.

Examples of the other monomer to be used for the silicone hydrogelcontact lens base material for the purpose of improving the shapemaintaining property of the contact lens include: alkyl (meth)acrylates,such as methyl (meth)acrylate and ethyl (meth)acrylate; siloxanemacromonomers having carbon-carbon unsaturated bonds at both terminalsthereof and polyfunctional (meth)acrylates, such as ethylene glycoldimethacrylate; halogenated alkyl (meth)acrylates, such astrifluoroethyl (meth)acrylate and hexafluoroisopropyl (meth)acrylate;aromatic vinyl monomers, such as styrene, α-methylstyrene, andvinylpyridine; and aliphatic vinyl monomers, such as vinyl acetate. Theusage amount of any such monomer is typically from 0.01 part by mass to30 parts by mass, preferably from 0.1 part by mass to 15 parts by masswith respect to 100 parts by mass of the monomer composition of thesilicone hydrogel contact lens base material.

The silicone hydrogel contact lens base material may be produced bymixing the respective monomers, and appropriately adding a thermalpolymerization initiator typified by a peroxide or an azo compound, or aphotopolymerization initiator to the mixture. When thermalpolymerization is performed, a thermal polymerization initiator having adecomposition characteristic optimum for a desired reaction temperaturemay be selected and used. For example, a peroxide or an azo compound,such as azobisisobutyronitrile, having a 10-hour half-life temperatureof from 40° C. to 120° C. may be used. The photopolymerization initiatormay be, for example, a carbonyl compound, a sulfur compound, a halogencompound, or a metal salt. Those polymerization initiators may be usedalone or as a mixture thereof. Any such initiator is preferably used ata ratio of from 0.05 part by mass to 2 parts by mass with respect to 100parts by mass of the polymerization components.

When Surface Treatment Object is Silicone Rubber

A silicone monomer to be used for a silicone rubber contact lens basematerial including, on its surface, the graft polymer containing aconstituent unit based on the monomer of the present invention is, forexample, a polyorganosiloxane for the purpose of improving the oxygenpermeability of the contact lens. For example, both-terminalsilanol-modified polydimethylsiloxane having a weight-average molecularweight of 330 (manufactured by Shin-Etsu Chemical Co., Ltd.) ispreferred. The usage amount of the silicone monomer is typically from 60parts by mass to 100 parts by mass, preferably from 75 parts by mass to95 parts by mass with respect to 100 parts by mass of the monomercomposition of the silicone rubber contact lens base material, and ispreferably from 75% to 95% in terms of a molar ratio.

The silicone rubber contact lens base material may be produced by mixingthe respective constituent units, and appropriately adding a curingcatalyst typified by a metal alkoxide to the mixture. Examples of themetal alkoxide may include aluminum isopropoxide and aluminum ethoxide.The curing catalysts may be used alone or as a mixture thereof. Thecuring catalyst is used at a molar ratio of typically less than 20%,preferably less than 10% with respect to the monomer composition of thesilicone rubber contact lens base material.

The production of the silicone rubber contact lens base material may beperformed in the presence of a solvent. The solvent is preferably asolvent that does not easily volatilize at room temperature, and is, forexample, toluene.

<Method of Producing Silicone Contact Lens Including, on Its Surface,Graft Polymer Containing Constituent Unit Based on Monomer of thePresent Invention>

Although a method of producing the silicone contact lens including, onits surface, the graft polymer containing a constituent unit based onthe monomer of the present invention is not particularly limited as longas a constituent unit represented by the formula (1′) is present on thesurface of the contact lens base material, a production method includingthe following steps may be given as an example thereof.

Step of Treating Surface of Contact Lens Base Material

In the method of producing the silicone contact lens of the presentinvention, in order that a constituent unit represented by the formula(1′) may be formed (coated or chemically modified) on the surface of thecontact lens base material, a peroxide (peroxide group) is formed on thesurface of the base material.

Step 1: A radical is formed on the surface of the contact lens basematerial (preferably a water-containing film-shaped contact lens basematerial). The radical formation method may be performed by, forexample, a plasma discharge treatment or excimer light irradiationtreatment known per se.

The plasma discharge treatment is performed under reduced pressure ornormal pressure (1.3 Pa to 0.1 MPa) and under an oxygen gas atmosphere,an inert gas atmosphere, or an air atmosphere for from 30 seconds to 30minutes. A pulse frequency is from 20 kHz to 25 kHz, and ahigh-frequency output is from 10 W to 500 W.

In the excimer light irradiation treatment, the surface is irradiatedwith vacuum UV light having a wavelength of 172 nm for from 30 secondsto 60 minutes.

Step 2: The contact lens base material having a radical formed on itssurface is placed under an oxygen gas atmosphere or an air atmospherefor from 1 minute to 2 hours so that the peroxide (peroxide group) maybe formed on the surface.

Step of bringing Contact Lens Base Material having Peroxide Group formedon its Surface and Mixed Solution containing Polyoxyethylene Compoundhaving Plurality of Hydroxyl Groups at Terminal thereof into Contactwith each other

In the method of producing the silicone contact lens including, on itssurface, the graft polymer containing a constituent unit based on themonomer of the present invention, the contact lens base material havinga peroxide group formed on its surface and a mixed solution containing apolyoxyethylene compound having a plurality of hydroxyl groups at aterminal thereof are brought into contact with each other. The mixedsolution containing the polyoxyethylene compound having a plurality ofhydroxyl groups at a terminal thereof contains at least the monomer ofthe present invention.

Although a method for the contact is not particularly limited, in orderthat the mixed solution can be sufficiently in contact with the entiretyof the surface of the contact lens base material, the base material ispreferably immersed in the mixed solution.

The concentration of the monomer of the present invention in the mixedsolution containing the polyoxyethylene compound having a plurality ofhydroxyl groups at a terminal thereof is from 0.01 mol/L to 1.0 mol/L.When the concentration is less than 0.01 mol/L, the surface of the basematerial cannot be subjected to graft polymerization with such an amountof the monomer that sufficient hydrophilicity and sufficient lubricitycan be imparted thereto. When the concentration is more than 1.0 mol/L,the viscosity of the solution increases to make it impossible to subjectthe surface to uniform graft polymerization. Accordingly, the smoothnessof the surface of the base material deteriorates, and hence the basematerial cannot be used as a contact lens.

Further, the concentration of all the monomers including the monomer ofthe present invention in the mixed solution containing thepolyoxyethylene compound having a plurality of hydroxyl groups at aterminal thereof is from 0.01 mol/L to 3.0 mol/L. When the concentrationis less than 0.01 mol/L, the surface of the base material cannot besubjected to graft polymerization with such an amount of the monomerthat sufficient hydrophilicity and sufficient lubricity can be impartedthereto. When the concentration is more than 3.0 mol/L, the viscosity ofthe solution increases to make it impossible to subject the surface touniform graft polymerization. Accordingly, the smoothness of the surfaceof the base material deteriorates, and hence the base material cannot beused as a contact lens.

The mixed solution containing the polyoxyethylene compound having aplurality of hydroxyl groups at a terminal thereof may contain ahydrophilic monomer (in particular, a hydrophilic ethylenicallyunsaturated monomer), a crosslinkable monomer, water, an organicsolvent, a chain transfer agent, and/or a polymerization sensitizer inaddition to the monomer of the present invention.

Examples of the hydrophilic monomer may include, but not particularlylimited to, the following. The monomers may be used alone or as amixture thereof.

(Meth)acrylic acid and various (meth)acrylates, such as methyl(meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl(meth)acrylate, benzyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate,3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and6-hydroxyhexyl (meth) acrylate.

Various polyoxyalkylene mono(meth)acrylates, such as polyoxyethylenemethyl ether (meth)acrylate and polyoxypropylene mono(meth)acrylate.

Various polymerizable amides, such as N-vinylformamide,N-vinylacetamide, N-acryloylmorpholine, N-vinyl-2-pyrrolidone,N-vinylpiperidone, N-vinylcaprolactam, N-vinylcaprylolactam,N,N-dimethyl(meth)acrylamide, and N-(meth)acryloyloxyethyl-2-pyrrolidone.

Preferred examples of the hydrophilic monomer may includepolyoxyethylene methyl ether methacrylate, polyethylene oxidemonoacrylate, 2-hydroxyethyl methacrylate, N-vinyl-2-pyrrolidone,methacrylic acid, and N,N-dimethylacrylamide.

The concentration of the hydrophilic monomer in the mixed solutioncontaining the polyoxyethylene compound having a plurality of hydroxylgroups at a terminal thereof is from 0 mol/L to 3.0 mol/L. When theconcentration falls within the range, an effect of blending thepolyoxyethylene compound can be obtained.

Examples of the crosslinkable monomer may include, but not particularlylimited to, the following. The monomers may be used alone or as amixture thereof.

Ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate,1,4-bis((meth)acryloyloxy)butane, 1,6-bis((meth)acryloyloxy)hexane,trimethylolpropane tri(meth)acrylate, pentaerythritoltetra(meth)acrylate, triallyl isocyanurate, diallyl phthalate, anddivinylbenzene.

Examples of the organic solvent may include, but not particularlylimited to, the following. The organic solvents may be used alone or asa mixture thereof.

Various alcohols, such as ethanol and methanol, acetone, benzene,toluene, acetonitrile, tetrahydrofuran, N,N-dimethylformamide, andmethylene chloride.

Examples of the chain transfer agent may include, but not particularlylimited to, the following. The chain transfer agents may be used aloneor as a mixture thereof.

α-Methylstyrene dimer and various mercaptans, such as n-butyl mercaptan,n-octyl mercaptan, n-lauryl mercaptan, n-dodecyl mercaptan, andt-dodecyl mercaptan.

Halogenated hydrocarbons, such as carbon tetrachloride and carbontetrabromide.

Other chain transfer agents, such as benzyl dithiobenzoate,1-phenylethyl dithiobenzoate, 2-phenyl-2-propynyl dithiobenzoate,1-acetoxyethyl dithiobenzoate, benzyl dithioacetate, t-butyldithiobenzoate, and 2-cyano-2-propynyl dithiobenzoate.

When the chain transfer agent is incorporated into the mixed solutioncontaining the polyoxyethylene compound having a plurality of hydroxylgroups at a terminal thereof, a residue derived from the chain transferagent at a terminal of a graft polymer chain length is produced aftergraft polymerization in some cases. In such cases, the residue ispreferably removed or transformed by being caused to react with asulfur-containing compound or an alkyl alcohol.

Examples of the polymerization sensitizer may include, but notparticularly limited to, compounds each having an anthracene skeleton,such as 9,10-bis(n-octanoyloxy)anthracene. The sensitizers may be usedalone or as a mixture thereof.

Step of Subjecting Surface of Contact Lens Base Material to GraftPolymerization with Polyoxyethylene Compound Having Plurality ofHydroxyl Groups at Terminal Thereof

In the method of producing the silicone contact lens of the presentinvention, a step of subjecting the surface of the contact lens basematerial to graft polymerization with the polyoxyethylene compoundhaving a plurality of hydroxyl groups at a terminal thereof may be, forexample, the following step, but is not particularly limited thereto.

The graft polymerization is performed as follows: under a state in whichthe contact lens base material having a peroxide group formed on itssurface and the mixed solution containing the polyoxyethylene compoundhaving a plurality of hydroxyl groups at a terminal thereof are broughtinto contact with each other, the surface is irradiated with UV light(200 nm to 450 nm or 200 nm to 380 nm) at an irradiance of from 0.5mW/cm² to 100 mW/cm² or from 0.5 mW/cm² to 15 mW/cm² for from 1 minuteto 1 hour at from 15° C. to 90° C.

After the graft polymerization, an unreacted component is removed asrequired. For example, a Soxhlet extraction method known per se is usedas a method for the removal.

Thus, the silicone contact lens including, on its surface, the graftpolymer containing a constituent unit based on the monomer of thepresent invention can be produced.

[Contact Lens Including Constituent Unit Based on Monomer of the PresentInvention]

A contact lens including a constituent unit based on the monomer of thepresent invention includes in itself a constituent unit represented bythe following formula (1′).

In the formula (1′), n represents from 2 to 2,260, and R¹ represents ahydrogen atom or a methyl group. When the n represents 1 or less,sufficient hydrophilicity and sufficient lubricity cannot be imparted tothe surface of a contact lens. When the n represents 2,261 or more, theviscosity of the monomer increases to make it difficult to uniformlytreat the surface of the contact lens with the monomer, and hence afunction of the contact lens is inhibited. The n is not particularlylimited as long as the n falls within the range of from 2 to 2,260, andthe n may represent from 2 to 250, from 17 to 200, from 50 to 150, from75 to 135, or from 90 to 120, and preferably represents from 17 to1,000, more preferably represents from 17 to 500, and most preferablyrepresents from 17 to 200.

The usage amount of the monomer of the present invention is typicallyfrom 1 part by mass to 40 parts by mass, preferably from 1 part by massto 20 parts by mass with respect to 100 parts by mass of the monomercomposition of the contact lens base material. When the usage amount isless than 1 part by mass, sufficient hydrophilicity and sufficientlubricity cannot be imparted to the surface of the base material, andwhen the usage amount is more than 40 parts by mass, theshape-maintaining property of the contact lens deteriorates.

A monomer that has been generally used as a monomer for a lens may beappropriately selected and used as any other monomer polymerizable withthe contact lens of the present invention.

For example, for controlling the water content of the contact lens,preferred examples of the water-soluble monomer include water-solublemonomers such as (meth)acrylic acid, itaconic acid, crotonic acid,cinnamic acid, vinylbenzoic acid, 2-((meth) acryloyloxy)ethyl-2′-(trimethylammonio) ethyl phosphate, phosphorylcholine(meth)acrylate, a polyalkylene glycol mono(meth)acrylate, a polyalkyleneglycol monoalkyl ether (meth)acrylate, 2-hydroxyethyl (meth)acrylate,glycerol (meth) acrylate, N-vinyl-2-pyrrolidone, N-vinylformamide,N-vinylacetamide, and N-methyl-N-vinylacetamide.

Of those, 2-hydroxyethyl (meth)acrylate is particularly preferred forthe purpose of controlling the water content. The total usage amount ofthe water-soluble monomer is typically from 10 parts by mass to 50 partsby mass, preferably from 20 parts by mass to 40 parts by mass withrespect to 100 parts by mass of the monomer composition of the siliconehydrogel contact lens base material.

Although the following silicone monomers each intended to improve theoxygen permeability of the contact lens may be given as examples of theother monomer polymerizable with the contact lens of the presentinvention, 3-[tris(trimethylsiloxy)silyl]propyl methacryloyloxyethylsuccinate (see WO 2010/082659 A1) is preferred.

Examples of (meth)acrylates each having a polydimethylsiloxane skeletoninclude α-methyl-ω-methacryloyloxypropyl polydimethylsiloxane(weight-average molecular weight: 1,000) and α,ω-dimethacryloyloxypropylpolydimethylsiloxane (weight-average molecular weight: 1,000). Forexample, FM-0711 or FM-7711 sold from JNC Corporation may be used.

Examples of (meth)acrylates each having a trimethylsiloxy group include3-[tris(trimethylsiloxy)silyl]propyl (meth)acrylate (TRIS),3-[bis(trimethylsiloxy)methylsilyl]propyl (meth)acrylate, and3-[(trimethylsiloxy)dimethylsilyl]propyl (meth)acrylate.

Examples of (meth)acrylamides each having a trimethylsiloxy groupinclude 3-[tris(trimethylsiloxy)silyl]propyl(meth)acrylamide,3-[bis(trimethylsiloxy)methylsilyl]propyl(meth)acrylamide, and3-[(trimethylsiloxy) dimethylsilyl]propyl (meth) acrylamide.

Examples of styrenes each having a trimethylsiloxy group include[tris(trimethylsiloxy)silyl]styrene,[bis(trimethylsiloxy)methylsilyl]styrene, and[(trimethylsiloxy)dimethylsilyl]styrene.

Examples of vinyl carbamates each having a trimethylsiloxy group includeN-[3-[tris(trimethylsiloxy)silyl]propyl] vinyl carbamate,N-[3-[bis(trimethylsiloxy)methylsilyl]propyl] vinyl carbamate, andN-[3-[(trimethylsiloxy)dimethylsilyl]propyl] vinyl carbamate.

The usage amount of the silicone monomer is typically from 10 parts bymass to 80 parts by mass, preferably from 40 parts by mass to 80 partsby mass with respect to 100 parts by mass of the monomer composition ofthe silicone hydrogel contact lens base material.

Examples of the other monomer polymerizable with the contact lens of thepresent invention for the purpose of controlling the flexibility of thecontact lens include a polyalkylene glycol bis(meth)acrylate,trimethylolpropane tris(meth)acrylate, pentaerythritoltetrakis(meth)acrylate, N,N-dimethylacrylamide, N,N-diethylacrylamide,N,N-di-n-propylacrylamide, N,N-diisopropylacrylamide,N,N-di-n-butylacrylamide, N-acryloylmorpholine, N-acryloylpiperidine,N-vinylcaprolactam, N-vinyloxazolidone, 1-vinylimidazole,N-vinylcarbazole, vinylpyridine, and vinylpyrazine. The usage amount ofthe monomer for controlling the flexibility of the contact lens istypically from 0 parts by mass to 50 parts by mass, preferably from 10parts by mass to 40 parts by mass with respect to 100 parts by mass ofthe monomer composition of the silicone hydrogel contact lens basematerial.

Examples of the other monomer polymerizable with the contact lens of thepresent invention for the purpose of improving the shape-maintainingproperty of the contact lens include: alkyl (meth)acrylates, such asmethyl (meth)acrylate and ethyl (meth)acrylate; siloxane macromonomershaving carbon-carbon unsaturated bonds at both terminals thereof andpolyfunctional (meth)acrylates, such as ethylene glycol dimethacrylate;halogenated alkyl (meth)acrylates, such as trifluoroethyl (meth)acrylateand hexafluoroisopropyl (meth) acrylate; aromatic vinyl monomers, suchas styrene, α-methylstyrene, and vinylpyridine; and aliphatic vinylmonomers, such as vinyl acetate. The usage amount of the monomer forimproving the shape-maintaining property of the contact lens istypically from 0.01 part by mass to 30 parts by mass, preferably from0.1 part by mass to 15 parts by mass with respect to 100 parts by massof the monomer composition of the silicone hydrogel contact lens basematerial.

The contact lens base material of the present invention can be producedby mixing the respective monomers, and appropriately adding a thermalpolymerization initiator typified by a peroxide or an azo compound, or aphotopolymerization initiator to the mixture. When thermalpolymerization is performed, a thermal polymerization initiator having adecomposition characteristic optimum for a desired reaction temperaturemay be selected and used. For example, a peroxide or an azo compound,such as azobisisobutyronitrile, having a 10-hour half-life temperatureof from 40° C. to 120° C. may be used. The photopolymerization initiatormay be, for example, a carbonyl compound, a sulfur compound, a halogencompound, or a metal salt. Those polymerization initiators may be usedalone or as a mixture thereof. Any such initiator is preferably used ata ratio of from 0.05 part by mass to 2 parts by mass with respect to 100parts by mass of the polymerization components.

After the polymerization, an unreacted component is removed as required.

Thus, the silicone contact lens including a constituent unit based onthe monomer of the present invention can be produced.

The present invention is also directed to a method of producing asilicone contact lens including, on its surface, a graft polymercontaining a constituent unit represented by the following formula (1′):

where n represents from 2 to 2,260, and R¹ represents a hydrogen atom ora methyl group.

The production method includes the following steps:

(I) a step of treating the surface of a contact lens base material;

(II) a step of bringing the contact lens base material obtained in thestep (I) and a mixed solution containing a polyoxyethylene compoundhaving a plurality of hydroxyl groups at a terminal thereof (monomerrepresented by the following formula (1)) into contact with each other;and

(III) a step of subjecting the surface of the contact lens base materialto graft polymerization with the polyoxyethylene compound having aplurality of hydroxyl groups at a terminal thereof.

The production method may further include the following step:

(IV) a step of removing an unreacted component.

where n represents from 2 to 2,260, and R¹ represents a hydrogen atom ora methyl group.

The present invention is also directed to a method of producing acontact lens including a constituent unit represented by the followingformula (1′):

where n represents from 2 to 2,260, and R¹ represents a hydrogen atom ora methyl group.

The production method includes the following steps:

(I) a step of mixing a monomer represented by the following formula (1),any other monomer polymerizable with the contact lens of the presentinvention, and a polymerization initiator; and

(II) a step of polymerizing the mixture obtained in the step (I).

The production method may further include the following step:

(III) a step of removing an unreacted component.

where n represents from 2 to 2,260, and R¹ represents a hydrogen atom ora methyl group.

The present invention is also directed to a surface treatment agent fora contact lens, including a polyoxyethylene compound represented by thefollowing formula (1):

where n represents from 2 to 2,260, and R¹ represents a hydrogen atom ora methyl group.

The present invention is also directed to a surface treatment method fora contact lens, including using a polyoxyethylene compound representedby the following formula (1):

where n represents from 2 to 2,260, and R¹ represents a hydrogen atom ora methyl group.

The present invention is also directed to a polyoxyethylene compound fora surface treatment of a contact lens, which is represented by thefollowing formula (1):

where n represents from 2 to 2,260, and R¹ represents a hydrogen atom ora methyl group.

The present invention is also directed to a use of a polyoxyethylenecompound represented by the following formula (1) as production of asurface treatment agent for a contact lens:

where n represents from 2 to 2,260, and R¹ represents a hydrogen atom ora methyl group.

EXAMPLES

The polyoxyethylene compound having a plurality of hydroxyl groups at aterminal thereof of the present invention, a silicone contact lensincluding, on its surface, a constituent unit based on the compound, anda contact lens including the constituent unit are described in moredetail on the basis of Examples.

Example 1

(Synthesis of Polyoxyethylene Intermediate 1)

200 g (40 mmol) of the polyoxyethylene compound “a” represented by theformula (2) (weight-average molecular weight: 5,000), and 800 g oftoluene were loaded into a 1-liter four-necked flask mounted with atemperature gauge, a nitrogen-blowing tube, a stirring machine, aDean-Stark tube, and a cooling tube. While the mixture was stirred andnitrogen was blown into the flask, the mixture was warmed to 40° C. todissolve the compound in toluene. The temperature of the solution wasincreased to 110° C., and about 200 g of a fraction was extracted whilethe solution was subjected to azeotropy with toluene, followed bydehydration. The residue was cooled to 30° C., and 12.14 g (0.12 mol) oftriethylamine and 8.36 g (80 mmol) of methacryloyl chloride were addedto the residue. The mixture was subjected to a reaction at 40° C. for 6hours.

After the reaction, triethylamine hydrochloride in the solvent wasseparated by filtration, and then the filtrate was cooled to roomtemperature. 600 g of ethyl acetate and 600 g of n-hexane were added tocrystallize the filtrate. After the crystal had been collected byfiltration, the crystal was dissolved in 1.6 kg of ethyl acetate at 35°C., and the solution was cooled to room temperature. After that, 400 gof n-hexane was added to crystalize the solution. The crystal wascollected by filtration and washed with 1.2 kg of n-hexane. The crystalwas collected by filtration and dried under a vacuum to provide 194 g ofa polyoxyethylene compound A (polyoxyethylene intermediate 1:weight-average molecular weight: 5,000) represented by the formula (3).The weight-average molecular weight of the synthesized polyoxyethyleneintermediate 1 was determined by gel permeation chromatography (GPC). Indetail, the weight-average molecular weight was measured as follows: adifferential refractometer was used as a detector, three columns, i.e.,SHODEX KF801L, KF803L, and KF804L (8 mmφ×300 mm) connected in serieswere used as a GPC column, the temperature of a column oven was set to40° C., tetrahydrofuran was used as an eluent, the flow rate of theeluent was set to 1 mL/min, the concentration of the sample was set to0.1 mass %, and the injection volume of the sample was set to 0.1 mL. Inaddition, the molecular structure of the resultant compound wasidentified by ¹H-NMR. The results of the ¹H-NMR analysis are describedbelow. A polymerization degree n of the sample was calculated bydividing the weight-average molecular weight determined from the GPC bythe formula weight thereof.

¹H-NMR (CDCl₃) δ (ppm): 1.36-1.41 (12H, m, —C(CH ₃)₂), 1.93 (3H, s,—C(CH ₃)═CH₂), 3.44-4.30 (513H, m, —O(CH ₂CH ₂O)_(n)—CH ₂CH—OC—),5.55-5.56 (1H, m, —C(CH₃)═CH ₂), 6.11 (1H, s, —C(CH₃)═CH ₂).

(Synthesis of Polyoxyethylene Compound 1)

200 g (40 mmol) of the polyoxyethylene intermediate 1 and 1.8 kg ofion-exchanged water were loaded into a 1-liter three-necked flaskmounted with a temperature gauge, a nitrogen-blowing tube, and astirring machine, and the intermediate was dissolved in theion-exchanged water while the mixture was stirred and nitrogen was blowninto the flask. Phosphoric acid was dropped to adjust the pH of thereaction liquid to 1, and the liquid was subjected to a reaction at roomtemperature for 3 hours.

After the reaction, 1.0 kg of chloroform was added to the resultant, andextraction was performed at room temperature twice, followed bydehydration with magnesium sulfate. After magnesium sulfate had beenseparated by filtration, the solvent was evaporated, and 1.0 kg of ethylacetate and 3.0 kg of n-hexane were added to crystallize the residue.The crystal was dissolved in 1.6 kg of ethyl acetate at 30° C., and thesolution was cooled to room temperature. After that, 1.6 kg of n-hexanewas added to crystalize the solution. The crystal was collected byfiltration and washed with 1.2 kg of n-hexane. The crystal was collectedby filtration and dried under a vacuum to provide 190 g of apolyoxyethylene compound 1 represented by the following formula (4) andhaving a weight-average molecular weight of 5,000. The weight-averagemolecular weight of the synthesized polyoxyethylene compound 1 wasdetermined through the use of GPC by the same method as that of thepolyoxyethylene intermediate 1. In addition, its molecular structure wasdetermined by ¹H-NMR. The results of the ¹H-NMR analysis are describedbelow.

¹H-NMR (CDCl₃) δ (Ppm): 1.92 (3H, s, —C(CH ₃)═CH₂), 3.30-4.30 (about510H, m, —O(CH ₂CH ₂O)_(m)—CH ₂CH—OH, —CHOH, —CH ₂OH), 5.55-5.56 (1H, m,—C(CH₃)═CH ₂), 6.11 (1H, s, —C(CH₃)═CH ₂).

<Method of Evaluating Surface Hydrophilicity>

The hydrophilicity of the surface of a contact lens was evaluated by thefollowing procedure. The contact lens was removed from a preservationsolution, and was washed in 200 mL of physiological saline three timesin order for the preservation solution adhering to the surface of thecontact lens to be removed therefrom. In a windless room, the contactlens was removed from the physiological saline and placed in front oflighting. A time period (WBUT) required for a water film to break toexpose the surface of the contact lens was recorded by visualobservation. A score of “0” was given to a case in which the WBUT wasless than 5 seconds, a score of “1” was given to a case in which theWBUT was 5 seconds or more and less than 15 seconds, and a score of “2”was given to a case in which the WBUT was 15 seconds or more.

<Method of Evaluating Surface Lubricity>

The lubricity of the surface of a contact lens was evaluated by thefollowing procedure. SEED 1 day Fine (trademark) (manufactured by SEEDCo., Ltd.) and PROCLEAR 1 day (trademark) (manufactured by CooperVisionJapan, Inc.) were used as the standards of a lubricity test. A producedwater-containing film was immersed in 10 mL of physiological saline, andwas shaken overnight. The water-containing film that had been immersedin the physiological saline and shaken overnight was removed and mountedon a forefinger, followed by the evaluation of its lubricity. Thelubricity evaluation was performed as follows: the lubricity was turnedinto a score in the range of from 1 point to 10 points while theevaluation score of the SEED 1 day Fine (trademark) (manufactured bySEED Co., Ltd.) immediately after its removal from a blister pack wasdefined as 2 points, and the evaluation score of the PROCLEAR 1 day(trademark) (manufactured by CooperVision Japan, Inc.) was defined as 8points.

Example 2-1

(Surface Treatment with Polyoxyethylene Compound 1)

60 Parts by mass of 3-[tris(trimethylsiloxy)silyl]propylmethacryloyloxyethyl succinate represented by the formula (5), 39 partsby mass of 2-hydroxyethyl methacrylate, 0.5 part by mass of ethyleneglycol dimethacrylate, and 0.5 part by mass of azobisisobutyronitrilewere mixed and dissolved. The solution was flowed into a cell sandwichedbetween a glass plate and a polypropylene plate through the use of apolyethylene terephthalate sheet having a thickness of 0.1 mm as aspacer. After an oven had been purged with nitrogen, the solution washeated at 100° C. for 2 hours to be polymerized, followed by moldinginto a film shape. Items to be evaluated in the present invention arehydrophilicity and lubricity, and hence the polymerized product wasmolded not into a lens shape but into the film shape for facilitatingthe performance of an experiment. After the polymerization, the curedfilm was removed from the cell, and was immersed in a mixed liquidcontaining ethyl alcohol (EtOH) and ion-exchanged water at a ratio of3/1 for 12 hours, and in ion-exchanged water for 12 hours to produce awater-containing film. The produced water-containing film was placed ina discharging apparatus, and a pressure in a chamber was reduced toabout 2.66 Pa. After that, a plasma discharge treatment was performedunder an oxygen gas atmosphere at about 13.3 Pa for 10 minutes(frequency: 13.56 MHz, high-frequency output: 50 W). After that, aperoxide (peroxide group) was produced on the surface of thewater-containing film by storing the water-containing film under anoxygen gas atmosphere for 10 minutes or more.

Next, the produced water-containing film was immersed in a compositioncontaining 5.5 w/w % (0.0101 mol/L) of the polyoxyethylene compound 1,0.05 w/w % of 9,10-bis(n-octanoyloxy)anthracene, and 94.45 w/w % oftoluene, followed by purging with nitrogen. After that, a coating filmof a hydrophilic graft polymer was formed on the surface of thewater-containing film by irradiating the surface with UV light(wavelength: 395 nm) at an irradiance of 50 mW/cm² under roomtemperature for 2 minutes. After the completion of the reaction, thewater-containing film was removed from the composition and washed withdistilled water, and extraction was performed with distilled water in aSoxhlet extractor for 16 hours to remove an unreacted residue from thewater-containing film. Thus, a water-containing film including, on itssurface, a graft polymer chain containing a constituent unit representedby the formula (1′) was produced. The water-containing film produced asdescribed in the foregoing was evaluated for its surface hydrophilicityand surface lubricity. The results are shown in Table 1.

Example 2-2 to Example 2-10

Water-containing films each including, on its surface, a graft polymerchain containing a constituent unit represented by the formula (1′) wereeach produced in accordance with the same procedure as that of Example2-1 except that components whose kinds and amounts were shown in Table 1were used. The surface hydrophilicity and surface lubricity of each ofExamples are shown in Table 1.

The term “polyoxyethylene compound 2” means a monomer having aweight-average molecular weight of 1,000 and represented by the formula(1) {in the formula (1), the polymerization degree n is 17, and the R¹represents a methyl group}. The term “polyoxyethylene compound 3” meansa monomer having a weight-average molecular weight of 10,000 andrepresented by the formula (1) {in the formula (1), the polymerizationdegree n is 222, and the R¹ represents a methyl group}. The term “PEG400monomethacrylate” means polyoxyethylene methyl ether methacrylate havinga weight-average molecular weight of 400.

As can be seen from the results shown in Table 1, in each of Examples2-1 to 2-3 and 2-7 to 2-10 (contact lenses each including, on itssurface, a graft polymer chain derived only from the monomer of thepresent invention), and Examples 2-4 to 2-6 (contact lenses eachincluding, on its surface, a graft polymer chain derived from themonomer of the present invention and a hydrophilic monomer), thewater-containing film including, on its surface, the graft polymer chaincontaining a constituent unit represented by the formula (1′) showedexcellent surface hydrophilicity and excellent surface lubricity.

Comparative Example 1-1

(Silicone Contact Lens Subjected to Surface Treatment with LowConcentration of Polyoxyethylene Compound 1)

A water-containing film was produced in the same manner as in Example2-1 except that components whose kinds and amounts were shown in Table 2were used. The produced water-containing film was immersed in acomposition containing a low concentration, i.e., 1 w/w % (0.0018 mol/L)of the polyoxyethylene compound 1, 0.05 w/w % of9,10-bis(n-octanoyloxy)anthracene, and 98.95 w/w % of toluene, followedby purging with nitrogen. After that, a coating film of a hydrophilicgraft polymer was formed on the surface of the water-containing film byirradiating the surface with UV light (wavelength: 395 nm) at anirradiance of 50 mW/cm² under room temperature for 2 minutes. After thecompletion of the reaction, the water-containing film was removed fromthe composition and washed with distilled water, and extraction wasperformed with distilled water in a Soxhlet extractor for 16 hours toremove an unreacted residue from the water-containing film. The resultsare shown in Table 2.

Comparative Example 1-2 and Comparative Example 1-3

(Surface Treatment with Graft Polymer Derived from Hydrophilic Monomer)

Water-containing films subjected to surface treatments with variouscompositions were each produced in accordance with the same procedure asthat of Comparative Example 1-1 except that components whose kinds andamounts were shown in Table 2 were used. The surface hydrophilicity andsurface lubricity of each of Comparative Examples are shown in Table 2.

As can be seen from the results shown in Table 2, the results ofComparative Example 1-1 were as follows: the blending amount of thepolyoxyethylene compound was less than 0.01 mol/L, and hence the surfacehydrophilicity and surface lubricity of the water-containing filmreduced. The results of each of Comparative Examples 1-2 and 1-3 were asfollows: the water-containing film did not include, on its surface, anygraft polymer chain containing a constituent unit represented by theformula (1′), and hence the surface hydrophilicity and surface lubricityof the water-containing film reduced.

It was confirmed from the foregoing results that the silicone contactlens of the present invention including, on its surface, a graft polymerchain containing a constituent unit represented by the formula (1′) hadexcellent surface hydrophilicity and excellent surface lubricity.

Example 3-1

(Contact Lens Including Constituent Unit Based on PolyoxyethyleneCompound 1)

20 Parts by mass of the polyoxyethylene compound 1, 50 parts by mass of3-[tris(trimethylsiloxy)silyl]propyl methacryloyloxyethyl succinate, 29parts by mass of 2-hydroxyethyl methacrylate, 0.5 part by mass ofethylene glycol dimethacrylate, and 0.5 part by mass ofazobisisobutyronitrile were mixed and dissolved. The solution was flowedinto a cell sandwiched between a glass plate and a polypropylene platethrough the use of a polyethylene terephthalate sheet having a thicknessof 0.1 mm as a spacer. After an oven had been purged with nitrogen, thesolution was heated at 100° C. for 2 hours to be polymerized, followedby molding into a film shape. Items to be evaluated in the presentinvention are surface hydrophilicity and surface lubricity, and hencethe polymerized product was molded not into a lens shape but into thefilm shape for facilitating the performance of an experiment. After thepolymerization, the cured film was removed from the cell, and wasimmersed in a mixed liquid containing ethyl alcohol (EtOH) andion-exchanged water at a ratio of 3/1 for 12 hours, and in ion-exchangedwater for 12 hours to produce a water-containing film. Thewater-containing film produced as described in the foregoing wasevaluated for its surface hydrophilicity and surface lubricity. Theresults are shown in Table 3.

The term “TRIS” means 3-[tris(trimethylsiloxy)silyl]propyl methacrylate.

Example 3-2 to Example 3-8

Water-containing films were each produced in accordance with the sameprocedure as that of Example 3-1 except that components whose kinds andamounts were shown in Table 3 were used. The surface hydrophilicity andsurface lubricity of each of Examples are shown in Table 3.

As can be seen from the results shown in Table 3, in each of Examples3-1 to 3-8, the water-containing film including a constituent unitrepresented by the formula (1′) showed excellent surface hydrophilicityand excellent surface lubricity.

Comparative Example 2-1

A water-containing film was produced in the same manner as in Example3-1 except that components whose kinds and amounts were shown in Table 4were used. The surface hydrophilicity and surface lubricity ofComparative Example 2-1 are shown in Table 4.

Comparative Example 2-2 to Comparative Example 2-4

(Surface Treatment with Graft Polymer Derived from Hydrophilic Monomer)

Water-containing films were each produced in accordance with the sameprocedure as that of Comparative Example 2-1 except that componentswhose kinds and amounts were shown in Table 4 were used. The surfacehydrophilicity and surface lubricity of each of Comparative Examples areshown in Table 4.

As can be seen from the results shown in Table 4, the results ofComparative Example 2-1 were as follows: when the polyoxyethylene methylether methacrylate that was not represented by the formula (1) and had aweight-average molecular weight of 400 was used as a polyoxyethylenecompound instead of the monomer of the present invention, the surfacehydrophilicity and surface lubricity of the water-containing film werelow. The results of each of Comparative Examples 2-2 to 2-4 were asfollows: when the water-containing film did not include any constituentunit based on a polyoxyethylene compound, the surface hydrophilicity andsurface lubricity of the water-containing film were low.

As can be seen from Comparative Examples 2-1 to 2-4 described above, thefollowing results were obtained: when a water-containing film did notinclude any constituent unit represented by the formula (1′), thesurface hydrophilicity and surface lubricity of the water-containingfilm were low.

It was confirmed from the foregoing results that a contact lensincluding a constituent unit based on the monomer of the presentinvention (constituent unit represented by the formula (1′)) hadexcellent surface hydrophilicity and excellent surface lubricity.

TABLE 1 Example Example Example Example Example Example Example ExampleExample Example 2-1 2-2 2-3 2-4 2-5 2-6 2-7 2-8 2-9 2-10 BlendingBlending Blending Blending Blending Blending Blending Blending BlendingBlending amount amount amount amount amount amount amount amount amountamount Component (w/w %) (w/w %) (w/w %) (w/w %) (w/w %) (w/w %) (w/w %)(w/w %) (w/w %) (w/w %) Polyoxyethylene compound 1 5.5 20 40 20 10 30 —— — — Polyoxyethylene compound 2 — — — — — — 2.5 10 25 — Polyoxyethylenecompound 3 — — — — — — — — — 11 PEG400 monomethacrylate — — — 10 — — — —— — 2-Hydroxyethyl methacrylate — — — 5 — — — — — —N-Vinyl-2-pyrrolidone — — — — 10 — — — — — Methacrylic acid — — — 5 10 —— — — — N,N-Dimethylacrylamide — — — — — 10 — — — — 9,10-Bis(n- 0.050.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 octanoyloxy)anthraceneToluene 94.45 79.95 59.95 59.95 69.95 59.95 97.45 89.95 74.95 88.95Polyoxyethylene compound 0.0101 0.0434 0.1157 0.0578 0.0248 0.08680.0222 0.0964 0.2892 0.0107 Molar concentration (mol/L) Total monomermolar 0.0101 0.0434 0.1157 1.8150 2.5797 1.5457 0.0222 0.0964 0.28920.0107 concentration (mol/L) Surface hydrophilicity 2 2 2 2 2 2 2 2 2 2Surface lubricity 9 9 10 9 9 10 9 10 10 9

TABLE 2 Comparative Comparative Comparative Example 1-1 Example 1-2Example 1-3 Blending Blending Blending amount amount amount Component(w/w %) (w/w %) (w/w %) Polyoxyethylene compound 1 1 — — 2-Hydroxyethylmethacrylate — 25 10 N-Vinyl-2-pyrrolidone — 15 — Methacrylic acid — 1010 N,N-Dimethylacrylamide — — 10 9,10-Bis(n-octanoyloxy) 0.05 0.05 0.05anthracene Toluene 98.95 49.95 69.95 Polyoxyethylene compound 0.00180.0000 0.0000 Molar concentration (mol/L) Total monomer molar 0.00187.6932 3.6425 concentration (mol/L) Surface hydrophilicity 1 0 0 Surfacelubricity 4 3 2

TABLE 3 Example Example Example Example Example Example Example Example3-1 3-2 3-3 3-4 3-5 3-6 3-7 3-8 Blending Blending Blending BlendingBlending Blending Blending Blending amount amount amount amount amountamount amount amount Component (w/w %) (w/w %) (w/w %) (w/w %) (w/w %)(w/w %) (w/w %) (w/w %) Polyoxyethylene 20 10 1 — — — — — compound 1Polyoxyethylene — — — 25 39 1 — — compound 2 Polyoxyethylene — — — — — —10 1 compound 3 2-Hydroxyethyl 29 19 18 29 20 38 39 5 methacrylateN-Vinyl-2-pyrrolidone — 10 20 — — — — 15 Methacrylic acid — — — 5 — — —— N,N-Dimethylacrylamide — — — — — — 10 —3-[Tris(trimethylsiloxy)silyl]propyl 50 60 60 40 40 60 — 78methacryloyloxyethyl succinate TRIS — — — — — — 40 — Ethylene glycol 0.50.5 0.5 0.5 0.5 0.5 0.5 0.5 dimethacrylate Azobisisobutyronitrile 0.50.5 0.5 0.5 0.5 0.5 0.5 0.5 Surface 2 2 2 2 2 2 2 2 hydrophilicitySurface lubricity 10 9 9 10 10 10 10 9

TABLE 4 Comparative Comparative Comparative Comparative Example 2-1Example 2-2 Example 2-3 Example 2-4 Blending Blending Blending Blendingamount amount amount amount Component (w/w %) (w/w %) (w/w %) (w/w %)2-Hydroxyethyl 29 29 34 19 methacrylate PEG400 20 — — — monomethacrylateN-Vinyl-2-pyrrolidone — 10 — 10 Methacrylic — — 5 — acidN,N-Dimethylacrylamide — — — 10 3-[Tris(trimethylsiloxy)silyl]propyl 5060 60 — methacryloyloxyethyl succinate TRIS — — — 60 Ethylene glycol 0.50.5 0.5 0.5 dimethacrylate Azobisisobutyronitrile 0.5 0.5 0.5 0.5Surface 0 0 0 0 hydrophilicity Surface 1 2 1 1 lubricity

INDUSTRIAL APPLICABILITY

The silicone contact lens having surface hydrophilicity and surfacelubricity is provided.

The invention claimed is:
 1. A silicone contact lens, comprising, on asurface thereof, a graft polymer containing a constituent unitrepresented by the following formula (1′):

where n represents from 2 to 2,260, and R¹ represents a hydrogen atom ora methyl group.
 2. A silicone contact lens according to claim 1, whereinthe n represents from 5 to 230, and the R¹ represents a methyl group. 3.A contact lens, comprising a constituent unit represented by thefollowing formula (1′):

where n represents from 2 to 2,260, and R¹ represents a hydrogen atom ora methyl group.
 4. A contact lens according to claim 3, wherein the nrepresents from 5 to 230, and the R¹ represents a methyl group.